Target Tracks Perception System

A developer implemented a perception system for game AI agents, adapted from Crytek's Target Tracks system. The system uses sight and awareness thresholds to track targets and adjust agent behavior, including turning toward perceived threats and changing alert states.

| // Adapted from Game AI Pro - Crytek’s Target Tracks Perception System | | | using System.Collections.Generic; | | | using UnityEngine; | | | namespace Perception { | | | public class PerceptionAgent : MonoBehaviour { | | | region Fields | | | Header "Sight" | | | SerializeField float viewRange = 15f; | | | SerializeField float primaryFov = 90f; | | | SerializeField float peripheralFov = 160f; | | | SerializeField LayerMask obstructionMask = ~0; | | | Header "Awareness" | | | SerializeField float alertThreshold = 25f; | | | SerializeField float highAlertEnter = 50f; | | | SerializeField float highAlertExit = 35f; | | | SerializeField float turnSpeed = 4f; | | | readonly Dictionary<Transform, TargetTrack tracks = new ; | | | readonly Dictionary<Transform, HashSet<StimType active = new ; | | | static readonly StimType allTypes = { StimType.VisualPrimary, StimType.VisualPeripheral, StimType.AudioMovement, StimType.AudioLoud }; | | | bool latchedHighAlert; | | | Renderer rend; | | | Material mat; | | | static readonly Color idle = new 0.2f, 0.8f, 0.3f , | | | suspicious = new 1f, 0.85f, 0.1f , | | | alert = new 1f, 0.2f, 0.15f ; | | | endregion | | | void LateUpdate { | | | ScanSight ; | | | TickTracks ; | | | React ; | | | active.Clear ; | | | } | | | void React { | | | TargetTrack best = null; | | | Transform bestTarget = null; | | | foreach var pair in tracks { | | | if best == null || pair.Value.Score best.Score { | | | best = pair.Value; | | | bestTarget = pair.Key; | | | } | | | } | | | var score = best = null ? best.Score : 0f; | | | var isPerceiving = bestTarget && active.TryGetValue bestTarget, out var set && set.Count 0; | | | if best = null && score = alertThreshold && isPerceiving { | | | var dir = best.LastKnownPosition - transform.position; | | | dir.y = 0f; | | | if dir.sqrMagnitude 0.01f transform.rotation = Quaternion.Slerp transform.rotation, Quaternion.LookRotation dir , turnSpeed Time.deltaTime ; | | | } | | | if score = highAlertEnter latchedHighAlert = true; | | | else if score < highAlertExit || score <= 0f latchedHighAlert = false; | | | if mat mat.color = latchedHighAlert ? alert : score = alertThreshold ? suspicious : idle; | | | } | | | void TickTracks { | | | var remove = new List<Transform ; | | | foreach var pair in tracks { | | | foreach var t in allTypes | | | pair.Value.Tick t, active.TryGetValue pair.Key, out var set && set.Contains t , Time.deltaTime ; | | | if pair.Value.Score <= 0f remove.Add pair.Key ; | | | } | | | foreach var t in remove tracks.Remove t ; | | | } | | | void ScanSight { | | | var player = GameObject.FindGameObjectWithTag "Player" ; | | | if player return; | | | var target = player.transform; | | | var eye = transform.position + Vector3.up; | | | var to = target.position + Vector3.up - eye; | | | var dist = to.magnitude; | | | if dist viewRange return; | | | var angle = Vector3.Angle transform.forward, to ; | | | StimType? type = null; | | | if angle <= primaryFov 0.5f type = StimType.VisualPrimary; | | | else if angle <= peripheralFov 0.5f type = StimType.VisualPeripheral; | | | if type == null || HasLineOfSight eye, to.normalized, dist, target return; | | | PerceptionHub.Emit new Stim type.Value, target, target.position, viewRange , transform ; | | | } | | | bool HasLineOfSight Vector3 origin, Vector3 direction, float distance, Transform target { | | | if Physics.Raycast origin, direction, out var hit, distance, obstructionMask return true; | | | return hit.transform == target || hit.transform.IsChildOf target ; | | | } | | | public void Receive Stim stim, Transform observer = null { | | | if stim.Type == StimType.VisualPrimary || stim.Type == StimType.VisualPeripheral { | | | if observer = transform return; | | | } | | | if stim.Source || Vector3.Distance transform.position, stim.Position RangeFor stim return; | | | if tracks.TryGetValue stim.Source, out var track { | | | track = new TargetTrack { Target = stim.Source }; | | | tracks stim.Source = track; | | | } | | | var config = ConfigFor stim.Type ; | | | track.Feed stim.Type, config.peak, config.attack, config.release, stim.Position ; | | | if active.TryGetValue stim.Source, out var set { | | | set = new HashSet<StimType ; | | | active stim.Source = set; | | | } | | | set.Add stim.Type ; | | | } | | | float RangeFor Stim s = s.Type == StimType.AudioMovement || s.Type == StimType.AudioLoud ? s.Radius : viewRange; | | | float peak, float attack, float release ConfigFor StimType t { | | | return t switch { | | | StimType.VisualPrimary = 100f, 2f, 40f , | | | StimType.VisualPeripheral = 40f, 4f, 40f , | | | StimType.AudioMovement = 25f, 1f, 8f , | | | = 80f, 0.5f, 18f | | | }; | | | } | | | void Awake { | | | rend = GetComponent<Renderer ; | | | if rend mat = rend.material; | | | } | | | void OnEnable = PerceptionHub.Register this ; | | | void OnDisable = PerceptionHub.Unregister this ; | | | } | | | } | | using System.Collections.Generic; | | | using UnityEngine; | | | using UnityEngine.Rendering; | | | namespace Perception { | | | public class PerceptionStimVisualizer : MonoBehaviour { | | | struct Pulse { | | | public StimType Type; | | | public Transform Source; | | | public Vector3 Position; | | | public float Radius; | | | public Transform Observer; | | | public float StartTime; | | | public float EndTime; | | | public int RingIndex; | | | public int BeamIndex; | | | public int BracketIndex; | | | public bool Alive float time = time < EndTime; | | | public void Refresh Vector3 pos, float linger { | | | Position = pos; | | | EndTime = Time.time + linger; | | | } | | | } | | | Header "Timing" | | | SerializeField float audioLinger = 0.4f; | | | SerializeField float visualLinger = 0.3f; | | | SerializeField float expandDuration = 0.5f; | | | Header "Ring" | | | SerializeField int ringSegments = 48; | | | SerializeField float ringWidth = 0.08f; | | | SerializeField float loudRingWidth = 0.14f; | | | Header "Sight Beam" | | | SerializeField float beamWidth = 0.06f; | | | SerializeField float bracketSize = 0.55f; | | | SerializeField float bracketHeight = 1.8f; | | | readonly List<Pulse pulses = new ; | | | readonly List<LineRenderer rings = new ; | | | readonly List<LineRenderer beams = new ; | | | readonly List<LineRenderer brackets = new ; | | | static readonly Color primaryColor = new 0.35f, 1f, 0.55f, 1f ; | | | static readonly Color peripheralColor = new 1f, 0.9f, 0.3f, 1f ; | | | static readonly Color walkColor = new 0.35f, 0.85f, 1f, 1f ; | | | static readonly Color sprintColor = new 1f, 0.55f, 0.2f, 1f ; | | | void OnEnable = PerceptionHub.StimEmitted += OnStim; | | | void OnDisable = PerceptionHub.StimEmitted -= OnStim; | | | void Awake { | | | EnsurePool rings, 16, "Ring" ; | | | EnsurePool beams, 8, "Beam" ; | | | EnsurePool brackets, 8, "Bracket" ; | | | } | | | void OnStim Stim stim, Transform observer { | | | var linger = IsAudio stim.Type ? audioLinger : visualLinger; | | | for var i = 0; i < pulses.Count; i++ { | | | var p = pulses i ; | | | if p.Type = stim.Type continue; | | | if IsAudio stim.Type && p.Source == stim.Source { | | | p.Refresh stim.Position, linger ; | | | pulses i = p; | | | return; | | | } | | | if IsAudio stim.Type && p.Observer == observer { | | | p.Refresh stim.Position, linger ; | | | pulses i = p; | | | return; | | | } | | | } | | | pulses.Add new Pulse { | | | Type = stim.Type, | | | Source = stim.Source, | | | Position = stim.Position, | | | Radius = stim.Radius, | | | Observer = observer, | | | StartTime = Time.time, | | | EndTime = Time.time + linger, | | | RingIndex = -1, | | | BeamIndex = -1, | | | BracketIndex = -1 | | | } ; | | | } | | | void LateUpdate { | | | var time = Time.time; | | | HidePool rings ; | | | HidePool beams ; | | | HidePool brackets ; | | | for var i = pulses.Count - 1; i = 0; i-- { | | | if pulses i .Alive time { | | | pulses.RemoveAt i ; | | | continue; | | | } | | | pulses i = DrawPulse pulses i , time ; | | | } | | | } | | | Pulse DrawPulse Pulse pulse, float time { | | | var linger = IsAudio pulse.Type ? audioLinger : visualLinger; | | | var fade = Mathf.Clamp01 pulse.EndTime - time / linger ; | | | var expand = Mathf.Clamp01 time - pulse.StartTime / expandDuration ; | | | var color = ColorFor pulse.Type ; | | | color.a = fade; | | | var ground = new Vector3 pulse.Position.x, pulse.Position.y + 0.05f, pulse.Position.z ; | | | if IsAudio pulse.Type { | | | pulse.RingIndex = DrawRing pulse.RingIndex, ground, pulse.Radius expand, color, pulse.Type == StimType.AudioLoud ? loudRingWidth : ringWidth ; | | | if pulse.Type == StimType.AudioLoud && expand 0.15f { | | | var echo = ColorFor pulse.Type ; | | | echo.a = fade 0.4f; | | | DrawRing -1, ground, pulse.Radius expand 0.5f, echo, ringWidth 0.55f ; | | | } | | | return pulse; | | | } | | | if pulse.Observer { | | | var eye = pulse.Observer.position + Vector3.up; | | | var target = pulse.Position + Vector3.up; | | | pulse.BeamIndex = DrawBeam pulse.BeamIndex, eye, target, color, beamWidth ; | | | } | | | var bracketCenter = pulse.Position + Vector3.up 0.5f; | | | pulse.BracketIndex = DrawBracket pulse.BracketIndex, bracketCenter, bracketSize, bracketHeight, color ; | | | DrawRing -1, ground, 0.5f + expand 0.5f, color, ringWidth 0.65f ; | | | return pulse; | | | } | | | int DrawRing int index, Vector3 center, float radius, Color color, float width { | | | if radius <= 0.01f return index; | | | var lr = Acquire rings, ref index ; | | | lr.enabled = true; | | | ApplyLine lr, color, width ; | | | lr.positionCount = ringSegments + 1; | | | lr.loop = true; | | | for var i = 0; i <= ringSegments; i++ { | | | var a = i / float ringSegments Mathf.PI 2f; | | | lr.SetPosition i, center + new Vector3 Mathf.Cos a radius, 0f, Mathf.Sin a radius ; | | | } | | | return index; | | | } | | | int DrawBeam int index, Vector3 from, Vector3 to, Color color, float width { | | | var lr = Acquire beams, ref index ; | | | lr.enabled = true; | | | ApplyLine lr, color, width ; | | | lr.loop = false; | | | lr.positionCount = 2; | | | lr.SetPosition 0, from ; | | | lr.SetPosition 1, to ; | | | return index; | | | } | | | int DrawBracket int index, Vector3 center, float size, float height, Color color { | | | var lr = Acquire brackets, ref index ; | | | lr.enabled = true; | | | ApplyLine lr, color, ringWidth ; | | | lr.loop = false; | | | lr.positionCount = 8; | | | var h = height 0.5f; | | | var s = size 0.5f; | | | lr.SetPosition 0, center + new Vector3 -s, -h, 0f ; | | | lr.SetPosition 1, center + new Vector3 -s, h, 0f ; | | | lr.SetPosition 2, center + new Vector3 -s 0.4f, h, 0f ; | | | lr.SetPosition 3, center + new Vector3 0f, h + s 0.35f, 0f ; | | | lr.SetPosition 4, center + new Vector3 s 0.4f, h, 0f ; | | | lr.SetPosition 5, center + new Vector3 s, h, 0f ; | | | lr.SetPosition 6, center + new Vector3 s, -h, 0f ; | | | lr.SetPosition 7, center + new Vector3 -s, -h, 0f ; | | | return index; | | | } | | | static bool IsAudio StimType t = t == StimType.AudioMovement || t == StimType.AudioLoud; | | | static Color ColorFor StimType t { | | | if t == StimType.VisualPrimary return primaryColor; | | | if t == StimType.VisualPeripheral return peripheralColor; | | | if t == StimType.AudioLoud return sprintColor; | | | return walkColor; | | | } | | | void EnsurePool List<LineRenderer pool, int count, string label { | | | for var i = pool.Count; i < count; i++ { | | | var go = new GameObject $"{label} {i}" ; | | | go.transform.SetParent transform, false ; | | | var lr = go.AddComponent<LineRenderer ; | | | lr.useWorldSpace = true; | | | lr.shadowCastingMode = ShadowCastingMode.Off; | | | lr.receiveShadows = false; | | | lr.material = new Material Shader.Find "Sprites/Default" ; | | | lr.enabled = false; | | | pool.Add lr ; | | | } | | | } | | | static void HidePool List<LineRenderer pool { | | | foreach var lr in pool lr.enabled = false; | | | } | | | static LineRenderer Acquire List<LineRenderer pool, ref int index { | | | if index < 0 || index = pool.Count || pool index .enabled { | | | index = -1; | | | for var i = 0; i < pool.Count; i++ { | | | if pool i .enabled { index = i; break; } | | | } | | | if index < 0 index = 0; | | | } | | | return pool index ; | | | } | | | static void ApplyLine LineRenderer lr, Color color, float width { | | | lr.startColor = lr.endColor = color; | | | lr.startWidth = lr.endWidth = width; | | | } | | | } | | | } | | using AdvancedController; // see https://www.youtube.com/watch?v=jSauntZrQro | | | using UnityEngine; | | | namespace Perception { | | | public class StimEmitter : MonoBehaviour { | | | SerializeField float walkSpeed = 1.5f; | | | SerializeField float sprintSpeed = 4f; | | | SerializeField float walkRadius = 8f; | | | SerializeField float sprintRadius = 18f; | | | PlayerController player; | | | Transform body; | | | void Awake { | | | player = GetComponent<PlayerController ; | | | body = transform; | | | } | | | void Update { | | | if player || body return; | | | var vel = player.GetMovementVelocity ; | | | var speed = vel.magnitude; | | | if speed < walkSpeed return; | | | var loud = speed = sprintSpeed; | | | PerceptionHub.Emit | | | new Stim | | | loud ? StimType.AudioLoud : StimType.AudioMovement, | | | body, | | | body.position, | | | loud ? sprintRadius : walkRadius | | | ; | | | } | | | } | | | } | | using System; | | | using System.Collections.Generic; | | | using UnityEngine; | | | namespace Perception { | | | public enum StimType { VisualPrimary, VisualPeripheral, AudioMovement, AudioLoud } | | | public static class PerceptionHub { | | | static readonly List<PerceptionAgent agents = new ; | | | public static event Action<Stim, Transform StimEmitted; | | | public static void Register PerceptionAgent agent = agents.Add agent ; | | | public static void Unregister PerceptionAgent agent = agents.Remove agent ; | | | public static void Emit Stim stim, Transform observer = null { | | | StimEmitted?.Invoke stim, observer ; | | | foreach var a in agents a.Receive stim, observer ; | | | } | | | } | | | public class TargetTrack { | | | public Transform Target; | | | public Vector3 LastKnownPosition; | | | readonly Dictionary<StimType, Envelope envelopes = new ; | | | public float Score { | | | get { | | | var max = 0f; | | | foreach var e in envelopes.Values | | | if e.Value max max = e.Value; | | | return max; | | | } | | | } | | | public void Feed StimType type, float peak, float attack, float release, Vector3 pos { | | | LastKnownPosition = pos; | | | if envelopes.TryGetValue type, out var env { | | | env = new Envelope ; | | | envelopes type = env; | | | } | | | env.Configure peak, attack, release ; | | | } | | | public void Tick StimType type, bool stimulated, float dt { | | | if envelopes.TryGetValue type, out var env env.Tick stimulated, dt ; | | | } | | | } | | | public class Envelope { | | | float value, peak, attackRate, releaseRate; | | | public float Value = value; | | | public void Configure float p, float attack, float release { | | | peak = p; | | | attackRate = p / Mathf.Max attack, 0.01f ; | | | releaseRate = p / Mathf.Max release, 0.01f ; | | | } | | | public void Tick bool stimulated, float dt { | | | if stimulated value = Mathf.Min peak, value + attackRate dt ; | | | else value = Mathf.Max 0f, value - releaseRate dt ; | | | } | | | } | | | public struct Stim { | | | public StimType Type { get; } | | | public Transform Source { get; } | | | public Vector3 Position { get; } | | | public float Radius { get; } | | | public Stim StimType type, Transform source, Vector3 position, float radius { | | | Type = type; | | | Source = source; | | | Position = position; | | | Radius = radius; | | | } | | | } | | | } |